Rotary head cleaning apparatus and magnetic recording-reproducing apparatus

ABSTRACT

A rotary head cleaning apparatus and method is disclosed, in which a control unit reserves recording times and operates a cleaning mechanism based on time information from a clock that measures time-of-day. The rotary head cleaning apparatus operates the cleaning mechanism when the time determined by the clock coincides with a non-reserved time other than times reserved for recording.

This application is a divisional of application Ser. No. 09/414,527,filed on Oct. 8, 1999 now U.S. Pat. No. 6,188,534 which is a divisionalof application Ser. No. 08/916,635, filed on Aug. 22, 1997 now U.S. Pat.No. 6,043,949 which is a divisional of application Ser. No. 08/509,657,filed on Jul. 31, 1995, now U.S. Pat. No. 5,701,224 which is acontinuation of application Ser. No. 08/188,785, filed on Jan. 31, 1994,now abandoned, the entire contents of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a rotary head cleaning apparatus forcleaning the rotary head mounted on the rotary drum such as a head for amagnetic recording and reproducing apparatus and to the magneticrecording-reproducing apparatus.

2. Description of Related Art

FIG. 1 is a perspective view showing a rotary drum and a video headcleaning mechanism for a conventional magnetic recording-reproducingapparatus. In this diagram, numeral 1 designates a rotary drum includinga rotatable upper drum 1 a and a lower drum 1 b making up a lead for atape guide. A head (not shown) is mounted on the peripheral surface ofthe upper drum 1 a. Tape guides 3 a, 3 b are arranged at the tape outletand the tape inlet, respectively, in the vicinity of the peripheralsurface of the rotary drum 1. A cleaning roller 2 is mounted in thevicinity of the peripheral surface of the rotary drum 1 through an arm 4coupled to the tape guide 3 a at the tape outlet side. The cleaningroller 2, which constitutes a video head cleaning mechanism, isoperatively interlocked with the tape guide 3 a, and the tape guide 3 amakes the peripheral surface of the roller come in contact with theperipheral surface of the rotary drum 1 at the tape outlet side in orderto clean the head, as follows.

When the magnetic recording-reproducing apparatus loads the tape for arecording or reproduction operation or unloads the tape after arecording or reproducing operation, the cleaning roller 2 comes incontact with the rotary drum 1, thereby cleaning the head.

The aforementioned conventional video cleaning mechanism is adapted toclean the head only at the time of loading or unloading. During acontinuous recording or reproduction for a long time, say, longer than100 hours, however, the head, which may be contaminated in the process,cannot be cleaned. After a long recording or a long reproduction, asingle cleaning operation could not clean off contaminationssufficiently. Nor is it possible to confirm whether the cleaning issufficient or not.

SUMMARY OF THE INVENTION

The invention has been developed in order to solve the above-mentionedproblem, and an object thereof is to provide a rotary head cleaningapparatus and a magnetic recording-reproducing apparatus capable ofcleaning the head sufficiently even in the case of a long recording orreproducing. The rotary head cleaning apparatus or the magneticrecording-reproducing apparatus using the same cleaning apparatusaccording to the invention comprises a cleaning mechanism adapted tocome in contact with the rotary drum for cleaning the head, a timesetter for setting an arbitrary time, and a cleaning controller foroperating the cleaning mechanism at the set time. The cleaning istherefore possible even during a long recording operation.

An alternative embodiment of the rotary head cleaning apparatus or themagnetic recording-reproducing apparatus using the same cleaningapparatus according to this aspect of the invention comprises a cleaningmechanism adapted to come into contact with a rotary drum for cleaningthe head, a time setter for setting an arbitrary time interval, and acleaning controller for operating the cleaning mechanism at set timeintervals. As a result, the periodic cleaning is possible even during along recording operation.

Another object of the invention is to provide a rotary head cleaningapparatus for keeping the head in satisfactory condition by cleaning thehead of a magnetic recording-reproducing apparatus a multiplicity oftimes using the cleaning apparatus. The rotary head cleaning apparatusof the magnetic recording-reproducing apparatus according to theinvention comprises a cleaning mechanism adapted to come in contact withthe rotary drum for cleaning the head, a power cut-off determiner fordeciding that power has been switched off for performing magneticrecording and/or magnetic reproducing function, and a cleaningcontroller for operating the cleaning mechanism when the decision ismade that the power is cut off. The apparatus further comprises anarbitrary time interval setter, and a cleaning controller for operatingthe cleaning mechanism at set time intervals. As a result, the cleaningoperation can be performed more often than can be done in theconventional apparatus, and the cleaning mechanism is operated when apower cut-off is decided, thereby permitting subsequent periodiccleaning operations. Also, the rotary head cleaning apparatus or themagnetic recording-reproducing apparatus using the same cleaningapparatus according to still another aspect of the invention comprises acleaning mechanism adapted to come in contact with the rotary drum forcleaning the head, a connection determiner for deciding that power forperforming the magnetic recording and/or magnetic reproducing functionis connected, and a cleaning controller for operating the cleaningmechanism when the connection determiner decides that power isconnected. In addition, the apparatus according to the inventioncomprises an arbitrary time interval setter, and a cleaning controllerfor operating the cleaning mechanism at set time intervals. As aconsequence, more cleaning operations can be performed than in the priorart, and the cleaning mechanism can be activated upon decision of apower connection, thereby to perform subsequent periodic cleaningoperations.

The rotary head cleaning apparatus or the magnetic recording-reproducingapparatus according to a further aspect of the invention comprises acleaning mechanism for cleaning the head, a recording reservation setterfor setting the reservation of the recording time, and cleaningcontroller for operating the cleaning mechanism when the present time isa non-reservation time, i.e., not within a reservation time zone. Inaddition, the apparatus comprises an arbitrary time interval setter, anda cleaning controller for operating the cleaning mechanism at set timeintervals. As a result, more cleaning operations can be performed thanin the prior art, and the cleaning mechanism is operated when thepresent time is in the non-reservation time zone to perform subsequentperiodic cleaning operations.

Still another object of the invention is to provide a magneticrecording-reproducing apparatus in which, after the head is cleaned, itis judged whether the head is sufficiently cleaned, thereby to keep thehead always in a well-cleaned condition. The magneticrecording-reproducing apparatus according to the invention comprises ahead mounted on the rotary drum, a signal processing circuit forprocessing signals to record and/or reproduce an object signal, acleaning mechanism adapted to come in contact with the rotary drum forcleaning the head, a cleaning judgement circuit for reproducing theobject signal, recorded after the cleaning operation, and judging thecleaning condition, and a cleaning controller for reactivating thecleaning mechanism in the case where an insufficient cleaning conditionis judged. As a result, the head is kept in an alwayssatisfactorily-cleaned condition.

The above and further objects and features of the invention will morefully be apparent from the following detailed description andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a rotary drum and a video headcleaning mechanism of a conventional magnetic recording-reproducingapparatus.

FIG. 2 is a schematic block diagram showing a configuration of amagnetic recording-reproducing apparatus according to a first embodimentof the invention.

FIG. 3 is a flowchart for explaining the head cleaning operation in asystem control circuit according to the first embodiment.

FIG. 4 is a flowchart for explaining the head cleaning operation in asystem control circuit according to a second embodiment.

FIG. 5 is a flowchart for explaining the head cleaning operation in asystem control circuit according to a third embodiment.

FIG. 6 is a flowchart for explaining the head cleaning operation in asystem control circuit according to a fourth embodiment.

FIG. 7 is a flowchart for explaining the head cleaning operation in asystem control circuit according to a fifth embodiment.

FIG. 8 is a flowchart for explaining the head cleaning operation in asystem control circuit according to a sixth embodiment.

FIG. 9 is a block diagram showing a configuration of a magneticrecording-reproducing apparatus according to a seventh embodiment.

FIG. 10 is a flowchart for explaining the head cleaning operation in asystem control circuit according to the seventh embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is described below with reference to the drawings showingembodiments thereof.

Embodiment 1

FIG. 2 is a schematic block diagram showing a configuration of amagnetic recording-reproducing apparatus comprising a video headcleaning apparatus according to the first embodiment of the invention.In the diagram, numeral 5 designates a deck of the magneticrecording-reproducing apparatus. The deck 5 includes a rotary drum 1carrying a head and a plurality of tape guides (not shown). The rotarydrum 1 and the tape guides have a configuration similar to that of theconventional apparatus shown in FIG. 1. The video signal inputted to thesignal processing circuit 9 is modulated at the signal processingcircuit 9 and outputted to and recorded by the recording head of thedeck 5. Also, the signal reproduced at the recording head is inputted toand demodulated at the signal processing circuit 9, so that ademodulated signal is outputted to a display unit.

A cleaning roller 2 is arranged in the vicinity of the peripheralsurface of the rotary drum 1. The peripheral surface of the cleaningroller 2 comes in contact with the peripheral surface of the rotary drum1, thereby to clean the head. This cleaning operation is performedindependently of the tape guides. The system control circuit 6 includinga microcomputer, together with the cleaning roller 2, makes up a videohead cleaning apparatus. This system control circuit 6 includes a timer11 for measuring the time and a register 10. A signal inputted to anoperating section 8 is stored in a register 10, and a signal forcontrolling the cleaning operation is outputted to the deck 5. Theoperating section 8 includes input keys for ordering the recording andreproducing of video signals, input keys for ordering the time intervalsfor head cleaning operations, and input keys for specifying the time forhead cleaning operations. The signal from the timer 11 is outputted to atime display unit 7 for making a time-related display.

In the magnetic recording-reproducing apparatus described above, theuser gives a signal for recording or reproducing the video signal to thedeck 5 through the system control circuit 6 by way of the operatingsection 8. At this time, the head is supplied with the video signal thathas been processed at the signal processing circuit 9, and the videosignal is recorded or reproduced by the head. Also, the user, by way ofthe operating section 8, inputs a signal for a cleaning operation to thesystem control circuit 6. As a result, the system control circuit 6performs the operations described below, thereby enabling the cleaningroller 2 to clean the head.

FIG. 3 is a flowchart for explaining the procedure for the head cleaningcontrol operation in the system control circuit 6. In the case where theuser sets a desired cleaning time or time intervals by the use of theoperating section 8, the signal is inputted to the system controlcircuit 6 to thereby decide whether the cleaning time intervals havebeen inputted (step S101). When the cleaning time intervals areinputted, the time of initial cleaning is determined on the basis of thetime intervals thus inputted (step S102), and the particular time isinputted to and stored in the register 10 (step S103). When the cleaningtime intervals are not inputted at step S101, on the other hand,decision is made as to whether the cleaning time has been inputted (stepS104). When the cleaning time is inputted, the particular cleaning timeis stored in the register 10 (step S103). Otherwise, step S101 and stepS104 are repeated until the cleaning time intervals or the cleaning timeis inputted.

Coincidence or non-coincidence between the present time based on thetimer 11 and the cleaning time is decided (step S105), and in case ofnon-coincidence, the same decision operation is repeated untilcoincidence is reached. At the time coincidence is reached, the cleaningroller 2 is brought into contact with the drum 1 and after performingthe head cleaning operation for a predetermined length of time, a signalfor restoring the cleaning roller 2 into the original position isinputted to the deck 5 (step S106). Whether a signal for ending the headcleaning operation has been inputted to the operating section 8 isdecided (step S107), and if it has been so inputted, the cleaningcontrol operation is terminated. If the signal has not yet beeninputted, the next cleaning time is calculated and then stored in theregister 10 (step S108) Whether the present time based on the timer 11and the cleaning time coincide with each other is then decided (stepS105) At a time point of coincidence, the deck 5 is supplied with asignal for causing the cleaning roller 2 to come in contact with thedrum 1 (step S106). This routine is then repeated.

In the video head cleaning apparatus having a configuration describedabove, the head is cleaned at the desired time intervals or at thedesired time of the day. Thus even in case of long recording orreproducing, the head can be cleaned a multiplicity of times.

Although the video head cleaned according to the first embodiment is forrecording or reproducing video signals, the invention is not limited tosuch a head but is applicable to a head dedicated to either therecording or the reproduction of a video signal with equal effect.

Embodiment 2

The configuration of the magnetic recording-reproducing apparatusaccording to a second embodiment of the invention is the same as thatshown in FIG. 2 except that the second embodiment includes input keysfor ordering the turning on and off of a power supply for the systemcontrol circuit 6 and the operating section 8. The procedure for theoperation of the system control circuit 6 will be described below, whileomitting the description of the other parts.

FIG. 4 is a flowchart for explaining the procedure for the head cleaningcontrol operation in the system control circuit 6 of the magneticrecording-reproducing apparatus according to the second embodiment ofthe invention. At first, the system control circuit 6 decides whetherthe power supply for recording or reproducing on the head is off (stepS201). In accordance with the signal inputted by the operation of theinput keys for ordering the turning on/off of the power supply, thesystem control circuit 6 outputs a signal for turning on/off the powersupply to the deck 5, thereby controlling the power supply for recordingor reproducing on the head. Whether or not the power supply is off isdecided by detecting a signal produced from the operating section 8 or asignal outputted from the system control circuit 6.

This decision is repeated until the power supply to the system controlcircuit 6 and the operating section 8 for recording or reproducing onthe head, which may be in an on state, turns off. At the time point whenthe power turns off, a signal is given to the deck 5 so that thecleaning drum 2 is brought into contact with the drum 1 to thereby cleanthe head for a predetermined time length (step S202). After the cleaningoperation is completed, it is decided whether the power supply forrecording or reproducing on the head is in an off state (step S203). Inthe case where the power supply is off, the decision is repeated untilthe power turns on. When the power supply to the system control circuit6 and the operating section 8 turns on, the cleaning control operationis terminated.

Although the video head cleaning operation according to the secondembodiment of the invention is performed on a head for both recordingand reproducing the video signal, the invention is not limited to suchapplications, but is equally applicable to the cleaning of a headcapable of only recording or reproducing a video signal.

Embodiment 3

Embodiment 2, described above, involves the case in which the head iscleaned once when the power supply to the system control circuit 6 andthe operating section 8 for head recording or reproducing is off.According to the third embodiment, however, the head is cleaned at settime intervals while the supply for head recording reproducing power isoff, thereby permitting a greater number of times of cleaning. FIG. 5 isa flowchart for explaining the procedure of the cleaning controlprocessing at the system control 6 described above. The apparatusaccording to the invention is similar to that of the second embodimentexcept that the operating section 8 of the magneticrecording-reproducing apparatus has input keys for ordering the turningon or off of the power supply for head recording or reproducing. Theremaining configurations are similar to those of the second embodimentand will not be described.

At first, the operating section 8 inputs the desired time intervals byway of input key operation for inputting the cleaning timing intervalsset in the operating section 8. It is thus decided whether the powersupply for a head recording or reproducing operation is off (step S301).In the case where the power supply is not off, the decision is repeateduntil the power is off. When the power supply turns off, a signal isinputted to the deck 5, so that the cleaning roller 2 is brought intocontact with the drum 1 to thereby clean the head for a pre-set timelength (step S302). In the process, the next cleaning time is determinedand inputted to the register 10 on the basis of the set cleaning timeintervals (step S303). After the cleaning is completed, it is decidedwhether the power supply is off (step S304). In the case where the powersupply is not off, the operation is ended. When the power for headrecording or reproducing is off, it is decided whether the present timeoutputted from the timer 11 and the cleaning time coincide with eachother (step S305). In the case where no coincidence is reached, thedecision at steps S304 and S305 are repeated until coincidence isreached. At the time of coincidence, a signal is given to the deck 5,and, with the cleaning roller 2 brought into contact with the drum 1,the head is cleaned for a pre-set time length (step S306). Aftercompletion of the pre-set duration of cleaning, whether the power supplyis off is decided (step S307). If the power supply is not off, theoperation is ended. If the power supply is off, the next cleaning timeis determined and given to the register 10 (step S308). The process isreturned to step S304 and it is decided whether the power is off. Thisroutine is then repeated.

The head is cleaned by a video head cleaning apparatus having aconfiguration as described above whereby, even in case of long recordingor reproducing operation, a greater number of head cleaning operationscan be performed than in the second embodiment, thereby providingsufficient means for coping with a stubborn contamination.

Although the video head cleaning according to third embodiment concernsa head for both recording and reproducing the video signal, theinvention is not confined to such an application but is also applicableto the cleaning of a head dedicated to only recording or reproducing ofthe video signal, with equal effect.

Embodiment 4

The configuration of the magnetic recording-reproducing apparatusaccording to the fourth embodiment of the invention is similar to thatshown in FIG. 2 except that there are provided input keys for giving anorder for the turning on/off of the power supply to the system controlcircuit 6 and the operating section 8. The procedure for the controloperation of the system control circuit 6 will thus be described belowwhile description of the other component parts will be omitted.

A flowchart for explaining the procedure for the head cleaning controloperation in the system control circuit 6 of the magneticrecording-reproducing apparatus according to the fourth embodiment isshown in FIG. 6. At first, the user inputs the desired cleaning timeintervals by way of an input key operation to input the cleaning timeintervals set in the operating section 8, thereby deciding whether thepower supply for a head recording/reproducing operation is on (stepS401). In the case where the power supply is not on, the decision isrepeated until the power supply is on. At the time when the power supplyturns on, a signal is given to the deck 5, whereupon the cleaning roller2 is brought into contact with the drum 1 to thereby clean the head fora predetermined length of time (step S402). On the basis of the cleaningtime intervals thus set, the next cleaning time is calculated andinputted to the register 10 (step S403).

After complete cleaning, it is decided whether the power supply is on(step S404). When the power is not on, the operation is terminated. Whenthe power supply is on, it is decided that the present time, based onthe timer 11, and the cleaning time are coincident with each other (stepS405). In case of non-coincidence, the decisions at step S404 and S405are repeated until a coincidence is reached. At the time of coincidence,a signal is inputted to the deck 5 so that the cleaning roller 2 isbrought into contact with the drum 1 to thereby clean the head for apredetermined time length (step S406). After the cleaning is completed,it is decided whether the power supply is on (step S407). If the powersupply is not on, the operation is terminated. If the power supply ison, the next cleaning time is determined and inputted to the register 10(step S408). The process is then returned to step S404, where it isdecided whether the power supply is on, to thereby repeat the routine.

Thus, the head is cleaned by a video head cleaning apparatus constructedas described above, whereby a multiplicity of head cleaning operationsare possible even during a long time recording or reproducing operation.

Although the foregoing description presupposes that the video headcleaning operation according to the fourth embodiment involves a headfor both recording and reproducing the video signal, the invention isnot limited to such an application, but is equally applicable to thecleaning of a head dedicated to only recording or reproducing a videosignal.

Embodiment 5

The magnetic recording-reproducing apparatus according to the fifthembodiment of the invention is constructed in the same way as theapparatus shown in FIG. 2, except that embodiment 5 further comprises asystem control circuit 6 and input keys included in the operatingsection 8 for inputting a time slot for record reservation. Theprocedure for the control operation of the system control circuit 6 isdescribed below, while the description of the other components will beomitted.

FIG. 7 is a flowchart for explaining the procedure for a head cleaningcontrol operation in the system control circuit 6 of the magneticrecording-reproducing apparatus according to the fifth embodiment of theinvention. First, the user sets the desired recording reservation timeslot by operating the input keys for recording the reservation on theoperating section 8. By so doing, a corresponding signal is inputted tothe system control circuit 6 to thereby prepare a recording reservationprogram containing the reserved starting time and finish time. Thesystem control circuit 6 detects one or more non-reserved time slotsfrom the recording reservation program (step S501). The non-reservedtime slot is defined as a time slot between a plurality of recordingreservation time slots or the time slot after the finish time of thefinal recording reservation time slot. As a result of detecting anon-reserved time slot, it is decided whether a plurality ofnon-reserved time slots are involved (step S502)

In the case where a plurality of the non-reserved time slots are notinvolved, i.e., there is but one non-reserved slot, a predetermined timepoint of the particular non-reserved time slot is determined, and it isdecided whether the predetermined time point and the present time fromthe timer 11 coincide with each other (step S503). According to theembodiment, the predetermined time point of the non-reserved time slotis set at the initial time point of the non-reserved time slot. Thispredetermined time point may alternatively be the one when a pre-settime passes in the non-reserved time slot. In case of non-coincidencebetween the predetermined time point and the present time, the samedecision is repeated until coincidence is reached. Upon coincidence, asignal is inputted to the deck 5, so that the cleaning roller 2 isbrought into contact with the drum 1 to thereby clean the head for apredetermined length of time (step S504). After cleaning is completed,the cleaning control operation is terminated.

In the case where it is decided at step S502 that there are involved aplurality of non-reserved time slots, a plurality of predetermined timepoints are determined in the particular non-reserved time slots, and itis decided whether these predetermined time points coincide with thepresent time based on the timer 11 (step S505). In case ofnon-coincidence the same decision is repeated until coincidence isreached.

When coincidence is obtained, a signal is inputted to the deck 5 so thatthe cleaning roller 2 is brought into contact with the drum 1 to therebyclean the head for a predetermined length of time (step S506). Aftercleaning is completed, it is decided again whether the present time andthe predetermined time point coincide with each other (step S507). Thedecision loop is repeated until such time as a coincidence is reached.Upon coincidence, decision is made as to whether the non-reserved timeslot involved is the last one detected (step S508). In the case wherethe detected non-reserved time slot is not the last one, the processreturns to step S506, where a similar operation is continued. When thedetected non-reserved time slot is the last one, on the other hand, thehead is cleaned in step S504, thus completing the cleaning controloperation.

By cleaning the head on a video head cleaning apparatus constructed asdescribed above, it is possible to clean the head a multiplicity oftimes even during the execution of a recording reservation.

Although the fifth embodiment concerns the cleaning of a head for bothrecording and reproducing a video signal, the invention is not limitedto such an application, but covers also a head used exclusively foreither video signal recording or reproducing.

Embodiment 6

The above-described fifth embodiment of the invention is a case in whichthe head is cleaned once during the non-reserved time slot. According tothe sixth embodiment of the invention, by contrast, the head is cleanedby the system control circuit 6 at set time intervals during a givennon-reserved time slot. This permits an even greater multiplicity ofcleaning operations. The operating section 8 of the magneticrecording-reproducing apparatus includes input keys for inputting thetime slot for recording reservation, the description of the othercomponent parts being omitted as they are the same as in the secondembodiment.

FIG. 8 is a flowchart for explaining the procedure for head cleaningoperation of the system control 6. The operating section 8 includesinput keys for inputting the starting time and finish time of therecording reservation time and input keys for inputting the cleaningtime intervals. At first, the user operates the input keys for settingthe desired recording reservation time slot and the desired cleaningtime intervals.

On the basis of the recording reservation time thus inputted, arecording reservation program is set, from which a non-reserved timeslot is detected (step S601), and the cleaning time is determined fromthe set cleaning time intervals (step S602). Decision is made as towhether a predetermined time point of the non-reserved time slotcoincides with the present time based on the timer 11 (step S608). Incase of non-coincidence, the decision step is repeated until coincidenceis reached. Upon coincidence, a signal is inputted to the deck 5 so thatthe cleaning roller 2 is brought into contact with the drum 1 to therebyclean the head for a predetermined length of time (step S604). Inaddition, the predetermined time point of the non-reserved time slot mayalternatively be the time point when a pre-set time of the non-reservedtime slot has passed.

After completion of cleaning, it is decided whether the present time isstill within the non-reserved time slot (step S605) and, when it is notwithin the non-reserved time slot, the cleaning control operation basedon the set time intervals is terminated. If within the non-reserved timeslot, decision is made as to whether the present time coincides with thecleaning time (step S606). In case of non-coincidence, the decision atstep S605 and step S606 are repeated until coincidence is reached. Atthe time point of coincidence, a signal is inputted to the deck 5, andthe cleaning roller 2 is brought into contact with the drum 1 to therebyclean the head for a pre-determined length of time (S607). Aftersuccessful completion of cleaning, the decision is made as to whetherthe present time is still within the non-reserved time slot (step S608).If not within the non-reserved time slot, the operation is completed. Ifthe present time is within the non-reserved time slot, the next cleaningtime is determined and inputted to the register 10 (step S609). Theprocess is then returned to step S605 for deciding whether the presenttime is still within the non-reserved time slot. This routine isrepeated.

By cleaning the head on a video head cleaning apparatus constructed asdescribed above, more head cleaning operations are made possible than inthe fifth embodiment even during the execution of a reserved time slot.

Although the video head cleaning operation according to the sixthembodiment concerns the cleaning of a head for both recording andreproducing a video signal, the invention is not confined to such acase, but it is also applicable to the cleaning of a head exclusive forrecording or reproducing of video signal.

Embodiment 7

FIG. 9 is a block diagram showing the configuration of a magneticrecording-reproducing apparatus according to a seventh embodiment of theinvention. The configuration of this magnetic recording-reproducingapparatus is similar to that of FIG. 2, except that the embodimentfurther comprises a signal processing circuit 9, a system controlcircuit 6, input keys for ordering the cleaning to the operating section8 and input keys for setting the maximum number of cleaning operations.FIG. 9 shows the signal processing circuit 9 and the system controlcircuit 6 in detail.

In the diagram, numeral 9 designated the signal processing circuit. Thiscircuit is for appropriately processing the input video signal to recordit in the magnetic tape 16 on the one hand, and for reproducing therecorded signal and processing the same signal to display it on thedisplay unit on the other. At first, a specific configuration of thesignal processing circuit 9 will be explained.

The video signal is inputted from an input terminal 32 to the signalprocessing circuit 9, wherein it is inputted at first to a separationcircuit 25 to be separated into a luminance signal and a chrominancesignal. The luminance signal thus separated is inputted to an FMmodulation circuit 23 through a first luminance signal processingcircuit 24, where it is FM-modulated. The chrominance signal, on theother hand, is then inputted through a first chrominance signalprocessing circuit 27 to a first chrominance low-pass converter circuit26 for conversion into a low frequency signal. The FM-modulatedluminance signal is synthesized with the chrominance signal after thelatter signal is converted into a low-frequency signal. The combinedsignal is outputted from the signal processing circuit 9, supplied tothe head 12 through a recording amplifier 17 and recorded in themagnetic tape 16.

Also, the signal recorded in the magnetic tape 16 is reproduced by thehead 12, amplified at a head amplifier 13, and inputted to an FMdemodulation circuit of the signal processing circuit 9 and a secondchrominance low-frequency conversion circuit 21. In the FM demodulationcircuit 18, the FM luminance signal is demodulated into a luminancesignal. In the second chrominance low-frequency converter circuit 21,the chrominance signal of 629 kHz±500 kHz is restored into a signal of3.58 Mhz±500 MHz. These values are for the case of NTSC televisionbroadcasting as in America. In the case of PAL broadcasting as inEurope, the signal is restored into a signal of 4.43 MHz±500 MHz. Theluminance signal is inputted to the second luminance signal processingcircuit 19. The chrominance signal, which is inputted to the secondchrominance signal processing circuit 22, on the other hand, issubjected to various processings including changing frequencycharacteristics, level conversion and noise reduction, after which thetwo signals are inputted to a mixer circuit 20 where the luminancesignal and the chrominance signal are synthesized. The video signal thussynthesized is produced from the signal processing circuit 9 through theoutput terminal 31 and is inputted to a display unit.

Next, a configuration of the system control circuit 6 will be explained.The signal reproduced by the head 12 and outputting from the headamplifier 13 is inputted to a signal processing circuit 9 as describedabove, while at the same time being inputted to an amplifier circuit 28and then to an integrating circuit 29. The integrating circuit 29integrates the inputted signal for converting the output amplitude fromthe head 12 into a voltage. The voltage thus converted is inputted to alevel detection circuit 30, where the output value from the head 12 isdetected and inputted to the system control section 31. The systemcontrol section 31 decides whether the cleaning of the head 12 isnecessary on the basis of the detected value.

The procedure for cleaning control operation by the system controlcircuit 6 in cleaning the head 12 using the magneticrecording-reproducing apparatus constructed as described above will beexplained on the basis of the flowchart of FIG. 10. The user operatesthe input keys for ordering the cleaning operation and for setting theupper limit of the number of cleaning operations on the operatingsection 8. Decision is made as to whether a signal representing thecleaning order for the head 12 and the set number (X) has been inputtedto the system control circuit 6 (step S701). When such a signal has notbeen inputted, the same decision loop is repeated until the signal isinputted. When the signal is inputted, the number of cleaning operations(n) is set to an initial value (N=1) (step S702). A cleaning ordersignal is inputted to the deck 5, and the cleaning roller 2 is broughtinto contact with the drum 1 to thereby clean the head for apredetermined length of time (step S703). After the predetermined lengthof cleaning, the number of times (n) is counted up to (N+1) (step S704),thereby deciding whether the set number (n) has reached the number oftimes (X) (step S705).

When the number (n) has not yet reached the set number (X), the videosignal inputted to the signal processing circuit 9 is recorded in themagnetic tape 16 for a predetermined length of time (step S706) Afterrecording, the magnetic tape 16 is rewound to the record starting point(step S707), and the recorded signal is reproduced (step S708).

The reproduced signal is inputted to the integrating circuit 29 and thelevel detection circuit for detecting the signal level. The systemcontrol section 31 decides whether the reproduced signal is higher thana predetermined level (step S709). When the reproduced signal is higherthan the predetermined level it is decided that the head 12 has beencleaned sufficiently, thus completing the cleaning control operation.When the reproduced signal is lower than the predetermined level, bycontrast, decision is made that the cleaning of the head 12 isinsufficient, so that the process returns to step S703 wherein the headis cleaned again followed by repetition of similar operations.

Also, when it is decided in step S705 that the number (n) has reachedthe set number (X), an external alarm signal is outputted (step S710).

With the video head cleaning apparatus as constructed above, it ispossible to confirm whether the cleaning of the head is sufficient.

The invention is not limited to the embodiment relating to the cleaningof a video head, but is also applicable to the cleaning of a headmounted on a rotary drum of an apparatus handling an audio signal suchas a DAT (Digital Audio Tape) recorder. In applying the seventhembodiment to a DAT, an audio signal is used as a signal forrecording/reproducing for the purpose of confirming the cleaningcondition.

It will thus be understood from the foregoing description that, in arotary head cleaning apparatus and a magnetic recording-reproducingapparatus using such a cleaning apparatus according to the invention, acleaning mechanism is driven at a set time or at set time intervals, andtherefore the head can be cleaned periodically even during a lengthyrecording operation. Also, since the cleaning mechanism is activated atthe time of connecting a power supply for recording and/or reproducing,the head can be cleaned during a lengthy recording operation. Further,the cleaning mechanism is operated at the time of power cut-off, therebypermitting the cleaning operation to be performed more frequently thanin the prior art. Furthermore, head cleaning during a lengthy recordingoperation is made possible by the fact that the cleaning mechanism isoperated in a time slot not reserved for recording a program. Also, thehead can always be kept in good condition in view of the fact that thevideo signal is recorded after cleaning, the cleaning condition isjudged from the reproduced output of the recorded portion to confirmwhether the cleaning is sufficient or not, and the cleaning operation isrepeated until the condition is satisfactory.

As this invention may be embodied in several forms without departingfrom the spirit or essential characteristics thereof, the presentembodiment is therefore illustrative and not restrictive. Thus, thescope of the invention is defined by the appended claims rather than bythe description preceding them, and all modifications that fall withinthe metes and bounds of the claims, or equivalent metes and boundsthereof, are intended to be embraced by the claims.

What is claimed is:
 1. A rotary head cleaning apparatus comprising: acleaning mechanism adapted to be brought into contact with a rotarydrum, for cleaning a head for magnetic recording and/or magneticreproducing, which is mounted on said rotary drum: means for decidingthat electric power supplied for a magnetic recording and/or magneticreproducing function has been switched on; and cleaning control meansfor operating said cleaning mechanism when said means for decidingdecides that the electric power has been switched-on.
 2. A rotary headcleaning apparatus according to claim 1, further comprising: means forsetting arbitrary time intervals; and time-measuring means for measuringa time; wherein said cleaning control means operates said cleaningmechanism when the time determined by said time-measuring meanscoincides with the time determined on the basis of the time intervalsset, after said means for deciding decides that the electric power hasbeen switched-on.
 3. A magnetic recording-reproducing apparatuscomprising: a head for performing magnetic recording and magneticreproducing; a rotary drum on which said head is mounted; a cleaningmechanism adapted to be in contact with said rotary drum for cleaningsaid head; means for deciding that electric power supplied for amagnetic recording and/or magnetic reproducing function has beenswitched-on; and cleaning control means for operating said cleaningmechanism when said means for deciding decides that the electric powerhas been switched-on.